Interactive systems commonly require users to utilize user names/passwords to access private information stored by servers. For instance, a web page that presents emails of users can require that the users input respective user names/passwords, and only upon proper authentication of entered user names/passwords will emails be presented. In this way, private or sensitive information of a user may be tightly controlled, and only provided upon stringent assurances that a person requesting the private or sensitive information has a right to the information.